Motor driven toothbrush, in particular an electric toothbrush

ABSTRACT

A motor-driven toothbrush including a brush head disposed at an angle to the brush handle wherein the brush head partakes of rotary or arcuate motion, wherein the handle includes a flexible or articulated section permitting the brush head and an end portion of the handle to deflect with respect to the remainder of the handle as the brush head engages the teeth. The elastic section may be a flexible portion or may be a bellows-like member. The drive for the brush head extends through the elastic section and to the brush head. The flexible section permits the brush head to tilt angularly through an angle either greater or less than 90 degrees with respect to the axis of the brush handle. The brush head is attachable to a separate handle having a drive device.

BACKGROUND OF THE INVENTION

The invention relates to a motor-driven toothbrush, in particular anelectric toothbrush, as one wherein the brush head partakes of anarcuate rotary-like motion, with the brush head angled to the normalaxis of the elongated housing or handle to which it is connected.

A toothbrush of this type is known, for example, from DE-U-295 20 230.0.In the case of this toothbrush, a housing head part, which receives arotatable bristle carrier, is fixedly connected to a housing part whichreceives a drive shaft arranged at right angles to the axis of rotationof the bristle carrier.

BRIEF SUMMARY OF THE INVENTION

The object of the present invention is to provide a toothbrush of thetype mentioned in the introduction by means of which a better cleaningaction can be achieved.

This object is achieved according to the invention by a toothbrushhaving the features of a brush head which is flexible and tiltable withrespect to the axis of the toothbrush housing or handle adjacent thebrush head.

Since the housing has a flexing zone and is subdivided by the latterinto two housing parts, which can be deflected elastically with respectto one another, with the result that, with forces acting in thedirection of the brushing surface, the brush head, which remains in adrive connection, can be forced back or pivoted elastically, use of thetoothbrush results in better abutment of the cleaning-action, brushingsurface and in an optimum contact pressure.

Preferred developments of the toothbrush are seen in the attacheddrawings. The invention embraces more than one embodiment as seen in thedrawings and described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of the toothbrush according to the invention isdescribed in more detail hereinbelow and is illustrated in the drawing,in which, purely schematically:

FIG. 1 shows a view of a first exemplary embodiment of a plug-on part ofan electric toothbrush;

FIG. 2 shows the longitudinal section of the plug-on part according toFIG. 1 in a normal position;

FIG. 3 shows the longitudinal section of the plug-on part according toFIG. 1 in a deflected position;

FIG. 4 shows a view of a second exemplary embodiment of a plug-on partof an electric toothbrush in the normal position, which corresponds toFIG. 2;

FIG. 5 shows a view of a third exemplary embodiment of a plug-on part ofan electric toothbrush in the normal position, which corresponds to FIG.2; and

FIG. 6 shows a view of a fourth exemplary embodiment of a plug-on partof an electric toothbrush in the normal position, which corresponds toFIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

According to FIGS. 1 to 3, a plug-on part 1 for an electric toothbrushhas a housing 2 which comprises a rear housing part 3, which can beplugged onto a handle part (not illustrated in the drawing), and a fronthousing part 4. A brush head 5 is mounted in the front housing part 4 ina rotatable manner, said brush head being driven by an electric motor(not illustrated in the drawing) by means of a transmission device 7,which is accommodated in a cavity 6 of the housing 2 and of which onlypart can be seen in FIGS. 2 and 3. The brush head 5 is imparted analternating rotary movement or rotary oscillation, it being possible forthe angle-of-rotation range to be adjusted. Such a toothbrush and such atransmission device form the subject matter of DE-U-295 20 230.0; thetransmission device 7 is thus not itself described in detailhereinbelow. A drive shaft of the transmission device 7 is designated by8, and the drive axis by A, in FIGS. 2 and 3. The brush-head axis isprovided with the designation B.

The brush head 5 has a bristle carrier 10 with projecting bristles 11.The free ends of the bristles 11 form a brushing surface 12. As anexample, a concave brushing surface 12 which is concentric to thebrushhead axis B is illustrated.

As can be seen from FIGS. 2 and 3, the bristle carrier 10 is connectedin the manner of a snap-action connection to a rotary plate 15, which ismounted in the housing part 4 in a rotatable manner, and can be removedfrom said rotary plate for the purpose of exchanging the brush head 5.The rotary plate 15, with the brush head 5, can be pivoted in bothdirections of rotation about an axial pin 16 which is provided in thehousing part 4 and is coaxial with the brush-head axis B. The rotaryplate 15 is secured axially in the housing part 4 by means of a securingpin 18 which projects into a circle-segment-type recess 17 in the rotaryplate 15 and is arranged radially with respect to the brush-head axis Bin the housing part 4.

The alternating rotary movement is transmitted from the drive shaft 8 tothe rotary plate 15 and to the brush head 5, which is connected to saidrotary plate, in the manner which is already known from DE-U-295 20230.0, namely by means of a protrusion 21 which is assigned to the driveshaft 8 and projects into a radial recess 20 in the rotary plate 15. Inthis case, the protrusion 21 is provided, in the contact region with therecess 20, with a spherical part 22. It is also possible, in the case ofthis embodiment of the toothbrush illustrated in FIGS. 1 to 3, for theangle range of the rotary pivoting of the rotary plate 15 and of thebrush head 5 to be adjusted by means of an axial displacement of thedrive shaft 8, which is provided with the protrusion 21. Thedisplacement of the drive shaft 8, and thus the radial adjustment of theprotrusion 21 in the recess 20, for the purpose of angle-rangeadjustment takes place by the action of switching over a slide 23 whichcan be adjusted into preferably two different switching positions.

According to the intention, a flexing zone 29. is located between therear housing part 3 and the front housing part 4, which is provided withthe brush head, with the result that during use of the toothbrush, withforces acting in the direction of the brushing surface 12, the housingpart 4, with the brush head 5, can be forced back elastically out of thenormal position, which is shown in FIG. 2, into a deflected position. Inthe case of the exemplary embodiment illustrated in FIGS. 1 to 3, thetwo housing parts 3, 4, which are produced from plastic, are separatefrom one another and connected to one another merely by means of anarticulated connection 24. The articulated connection 24 comprises athin plastic hinge 25 (film hinge), which forms the pivot axis of thehousing part 4, and an articulation sleeve 26. The hinge 25 is arrangedat right angles to a plane defined by the brush-head axis B and thedrive axis A, which at the same time forms the longitudinal axis of thehousing part 3; the pivot axis thus runs perpendicularly with respect tothe plane of the drawing.

The articulation sleeve 26, made of an elastomeric material, isinstalled between the two housing parts 3, 4 or between the mutuallyfacing end surfaces 27, 28 of the same--such that it tapers toward thehinge 25 in the form of a wedge.

In the case of the preferred embodiment illustrated, the front housingpart 4, which is provided with the brush head 5, can be forced back orpivoted with respect to the rear housing part 3, in the clockwisedirection according to FIG. 2, approximately by 6° about the pivot axisdefined by the hinge 25. In this case, the elastomeric articulationsleeve 26 is compressed, the wedge-shape space between the head part 4and the housing part 3 is reduced, and the elastomeric material bulgessome way towards outward on the side remote from the hinge 25 (FIG. 3).As soon as the action of force on the brush head 5 is eliminated, thehead part 4, with the brush head 5, returns, under the action of theelastomeric articulation sleeve 26 being relieved of pressure, into theneutral position, which is illustrated in FIG. 2. However, the flexingzone could be designed such that pivoting of the housing part 4,provided with the brush head 5, in the angle range of up to 90° would bepossible.

In the case of the embodiment which is illustrated in FIGS. 2 and 3, theprotrusion 21 in the normal position, according to FIG. 2, projects intothe recess 20 of the rotary plate 15 with play, i.e. not quite as far asthe bristle carrier 10; in the deflected position, which is shown inFIG. 3, the protrusion 21 is located in the immediately vicinity of thebristle carrier 10. In both end positions of the housing part 4,engagement of the protrusion 21 in the recess 20 is ensured. In eachpivot position of the housing part 4, the spherical part 22 of theprotrusion 21 permits satisfactory transmission of movement to therotary plate 15 and friction-free pivoting of the housing part 4.

If the brush head 5 in operation is forced back out of the normalposition by the forces acting in the direction of the brushing surface12, then the position of the protrusion 21 in the radial recess 20changes, i.e. the distance between the protrusion 21 and the axial pin16, which defines the axis of rotation B of the brush head 5, isreduced. This results in the angle of rotation of the brush head 5 beingreduced Without there having to be a change in the angle of rotationfrom the outside. In other words, the angle of rotation of the brushhead 5 decreases as the compressive forces acting on the brush head 5increase.

However, it would also be possible for the drive shaft 8 of thetransmission device 7 to be designed such that it can go along with thedeflection of the housing part 4 and of the rotary plate 15, mounted insaid housing part, so that, when the housing part 4 pivots, theprotrusion 21 remains satisfactorily. in engagement with the recess 20.For this purpose, the drive shaft may be configured, for example, as aflexible shaft or may be provided with a universal joint.

The elastic deflectability of the housing part 4, which receives thebrush head 5, achieves, during use of the toothbrush, better abutment ofthe cleaning-action, brushing surface 12 and an optimum contactpressure.

In the case of the exemplary embodiment illustrated, the angle betweenthe brush-head axis B and the drive axis A before pivoting, i.e. in theneutral position, is somewhat smaller than 90°, i.e. the brush head 5 isinclined some way rearward. In the position with maximum deflection,this angle is somewhat greater than 90°; i.e. the brush head 5 isinclined some way forward. However, it would also be possible to aim forother angle relationships of the two axes in the end positions.

In the case of the embodiment which is illustrated in FIGS. 1 to 3, thepivot axis or the hinge 25 is located on the bottom side of the housing2 and the elastomeric articulation sleeve 26 is subjected to compressiveloading when the housing part 4 is forced back. However, it would alsobe possible for the pivot axis or the hinge 25 to be placed on the topside of the housing 2, with the result that, instead of being subjectedto compressive loading, the elastomeric articulation sleeve would besubjected to tensile loading if the housing part 4 were pivoted.

The plug-on part 1 may be produced, for example, by two-componentinjection molding.

FIG. 4 shows a second exemplary embodiment of a plug-on part 1a for anelectric toothbrush. In the case of this exemplary embodiment, the twohousing parts 3a, 4a are connected to one another preferably via narrow,flexible webs (which cannot be seen in FIG. 4). While the two housingparts 3a, 4a and the housing region 33, which is formed by the webs, areproduced from the same material, a sleeve-like bellows 36 which is madeof different, elastomeric material is installed between mutually facingend surfaces 37, 38 of the two housing parts 3a, 4a, said bellows,together with the housing region 33, forming the flexing zone 29a. Whenthe housing part 4a, which is provided with the brush head 5, is forcedback, the bellows 36 is subjected to compressive loading.

It is also the case with the third embodiment, which is illustrated inFIG. 5, of a plug-on part 1b that the housing 2b has an elasticallyflexible housing region 33 which connects the two housing parts 3b, 4band is preferably formed by narrow webs (which cannot be seen). Abellows 41, which forms the flexing zone 29b together with the housingregion 33, is installed between end surfaces 39, 40 of the two housingparts 3b, 4b and is made of an elastomeric material, which is differentfrom the material of the two housing parts 3b, 4b and the webs, issubjected both to compressive loading and to tensile loading when thehousing part 4b, which is provided with the brush head 5, is forcedback.

The plug-on parts 1a, 1b are also suitable for production bytwo-component injection molding.

A further embodiment of a plug-on part 1c according to FIG. 6constitutes a single-component embodiment; the two housing parts 3c, 4cas well as the entire housing wall, and the elastically deformablehousing region 43 in the flexing zone 29c, is are produced from the samematerial and, again, preferably comprises the narrow webs (which cannotbe seen in FIG. 6), connecting the two housing parts 3c, 4c, andadditionally a sleeve-like part 44. The elastically deformable part 44,which assumes the function of the bellows 36, 41 according to FIGS. 4and 5, may have a plurality of through-passages 45 for the purpose ofincreasing the elasticity.

With all of the embodiments described above, it would also be possiblefor the flexing zone 29 or 29a or 29b or 29c to be arranged furthertoward the rear in the direction of the handle.

The flexing zone may be configured such that, in addition to thathousing part which bears the brush head 5 being pivoted in the planedefined by the brush-head head axis B and the longitudinal axis of theplug-on part, additional lateral pivoting of the same may also takeplace. This can be made possible, for example, by those embodiments ofthe flexing zone which are illustrated in FIGS. 4 to 6. However, otherconfigurations with elastic rings or folds would also be conceivable.

The deflectability according to the invention of that housing part whichreceives the brush head could, of course, also be used for brush headswhich, rather than being driven in an alternating manner, are driven inone direction of rotation.

The invention claimed is:
 1. A motor-driven toothbrush, in particular anelectric toothbrush, comprising:an elongate housing (2, 2a, 2b, 2c)which has a cavity (6) on the inside, a brush head (5) mounted to thehousing (2, 2a, 2b, 2c) in a rotatable manner, said brush head having abristle carrier (10) with projecting bristles (11), wherein the bristleends form a brushing surface (12), and wherein the axis of rotation (B)of the brush head (5) is arranged at an angle to the longitudinal axis(A) of the housing (2, 2a, 2b, 2c), a transmission device (7) in thecavity of the housing (2, 2a, 2b, 2c) for coupling to a drive wherebythe brush head (5) can be driven in a rotatable manner, wherein thehousing (2, 2a, 2b, 2c) has a flexing zone (29, 29a, 29b, 29c)subdividing the housing into two housing parts (3, 3a, 3b, 3c; 4, 4a,4b, 4c) which can be deflected elastically relative to one another suchthat with forces acting in the direction of the brushing surface (12),the brush head (5) can be forced back or pivoted elastically in a planedefined by the axis of rotation (B) of the brush head and thelongitudinal axis (A) of the housing (2, 2a, 2b, 2c), wherein furtherthe housing (2, 2a, 2b, 2c) is attachable to a separate handle partwhich is provided with the drive for coupling to the said transmissiondevice (7), and, wherein the transmission device (7) includes structurefor maintaining a drive connection to the brush head (5) even when thehousing parts (3, 3a, 3b, 3c; 4, 4a, 4b, 4c) are deflected relative toone another.
 2. The toothbrush as claimed in claim 1, wherein theflexing zone (29a or 29b or 29c) comprises an elastically deformablehousing region (33 or 43) which connects the two housing parts (3a, 3b,3c; 4a, 4b, 4c) to one another.
 3. The toothbrush as claimed in claim 2,wherein the elastically deformable housing region (33 or 43) comprisesnarrow webs which connect the two housing parts (3a, 4a or 3b, 4b or 3c,4c).
 4. The toothbrush as claimed in claim 3, wherein, together with theelastically deformable housing region (33 or 43), a sleeve-like bellows(36 or 41), which is installed between mutually facing end surfaces (37,38 or 39, 40) of the two housing parts (3a, 4a or 3b, 4b), forms theflexing zone (29a or 29b).
 5. The toothbrush as claimed in claim 3,wherein the elastically deformable housing region (43) is produced fromthe same material as the two housing parts (3c, 4c) and has asleeve-like part (44) which is preferable provided with through-passagesfor the purpose of increasing the elasticity.
 6. The toothbrush asclaimed in claim 2 wherein, together with the elastically deformablehousing region (33 or 43), a sleeve-like bellows (36 or 41), which isinstalled between mutually facing and surfaces (37, 38 or 39, 40) of thetwo housing parts (3a, 4a or 3b, 4b), forms the flexing zone (29a or29b).
 7. The toothbrush as claimed in claim 2, wherein the elasticallydeformable housing region (43) is produced from the same material as thetwo housing parts (3c, 4c) and has a sleeve-like part (44) which ispreferably provided with through-passages for the purpose of increasingthe elasticity.
 8. The toothbrush as claimed in claim 1, wherein theflexing zone (29) comprises an articulated connection (24) between thetwo housing parts (3, 4).
 9. The toothbrush as claimed in claim 8,wherein the articulated connection (24) comprises a hinge (25), whichforms a pivot axis arranged at right angles to the plane defined by theaxis of rotation (B) of the brush head and the longitudinal axis (A) ofthe housing (2), and an elastomeric articulation sleeve (26) between thetwo housing parts (3, 4).
 10. The toothbrush as claimed in claim 9,wherein the elastomeric articulation sleeve (26) is installed betweenmutually facing end surfaces (27, 28) of the two housing parts (3, 4) inthe form of a wedge which tapers toward the hinge (25).
 11. Thetoothbrush as claimed in claim 1 having a drive shaft (8) which isarranged in the cavity (6) of the housing (2, 2a, 2b, 2c) and forms partof the transmission device (7), wherein the drive shaft (8) is designedas a flexible shaft.
 12. The toothbrush as claimed in claim 1 whereinthat part of the transmission device (7) which is assigned to thedeflectable housing part (4, 4a, 4b, 4c) is connected via a universaljoint to that part of the transmission device (7) in the other housingpart (3, 3a, 3b, 3c).
 13. The toothbrushes claimed in one of claim 1wherein the deflection of the housing part (4, 4a, 4b, 4c) and thechange in the angle between the axis of rotation (B) of the brush headand the longitudinal axis (A) takes place in the angle range of from 0°to 90°.
 14. The toothbrush as claimed in claim 13 wherein the angle isapproximately 6°.
 15. The toothbrush as claimed in claim 1, wherein theangle between the axis of rotation (B) of the brush head and thelongitudinal axis (A) is somewhat smaller than a right angle in a normalposition and somewhat greater than a right angle in a position ofmaximum deflection, i.e. the brush head (5) is inclined rearward in thenormal position and forward in the deflected position.
 16. Thetoothbrush as claimed in claim 1 having a brush head (5) which executesan alternating rotary movement, wherein the transmission device (7) hasstructure whereby when the brush head (5) is forced back, as a result offorces acting in the direction of the brushing surface (12), the angleof alternating rotation of said brush head decreases.